Diseases and disorders of the gallbladder, pancreas, and bile ducts (e.g., pancreaticobiliary system) are associated with significant morbidity, mortality, and impaired quality of life. Obstructions, tumors, injuries, leakages, and lesions can occur in these structures, which can eventually lead to conditions such as biliary colic, cholecystitis, choledocholithiasis, cholelithiasis, pancreatitis, pancreatic duct stone formations, and chronic abdominal pain. In addition, diseases/disorders of the pancreaticobiliary system may be associated with nutritional disorders, such as malnutrition, obesity, as well as high cholesterol.
FIG. 1 illustrates a portion of the human body, including the pancreaticobiliary system. The liver 100 produces bile, a fluid vital for the digestion of fatty foods. Bile contains salts, cholesterol, various pigments, and waste products such as bilirubin. Bile serves at least two main functions: to get rid of certain waste products; and to aid in digestion by assisting in the emulsification and absorption of fats from the intestines. Bile is collected by a network of ducts that converge at the common hepatic duct 102. While a small quantity of bile drains directly into the lumen of the duodenum 120 (an upper part of the small intestine immediately downstream of the stomach), most bile travels through the common hepatic duct 102 and accumulates within the gallbladder 104. Contraction of the gallbladder 104 forces bile to flow from the gallbladder 104, through the cystic duct 106, and into a large bile duct known as the common bile duct 108. From the common bile duct 108, bile flows through the ampulla of Vater 118 and into the duodenum 120, where the bile mixes and reacts with digesting food.
The pancreas 114 is both an endocrine gland (producing several important hormones, including insulin, glucagon, and somatostatin), as well as an exocrine gland, secreting pancreatic juices containing digestive enzymes that pass to the small intestine. The pancreatic duct 112 joins the common bile duct 108 just prior to the ampulla of Vater 118. Accordingly, pancreatic juices drain through the ampulla of Vater 118 and into the duodenum to further aid in digestion.
The common bile duct and pancreatic duct are essential for providing drainage from the liver, gallbladder, and pancreas. However, in some cases, these ducts may become obstructed as a result of cysts, enlarged lymph nodes, gallstones, inflammation, stricture, or narrowing, of the ducts from scarring, injury from surgery, tumors, or other causes, which can lead to inadequate drainage of bile and/or pancreatic juices.
For example, as shown in FIG. 2, a common problem that arises in the biliary system is the formation of gallstones, a condition called cholelithiasis. Gallstones can form in the gallbladder 104, cystic duct 106, and/or the common bile duct 108. By themselves, gallstones 110 do not necessarily result in disease states. However, stones can cause infection and inflammation, a condition known as cholecystitis, which is generally the result of restricting or blocking the flow of bile from the gallbladder 104 and common bile duct 108, or the fluids secreted by the pancreas 114. When gallstones 110′ become lodged in the common bile duct 108, the condition is known as choledocholithiasis. Symptoms for this condition include pain, nausea and vomiting, and some patients develop jaundice, have dark urine and/or lighter stools, rapid heartbeat, and experience an abrupt drop in blood pressure. Blockages in the bile ducts may also be caused by other obstructions, including, but not limited to, tumors, inflammation due to trauma or illness, such as pancreatitis, infection, improper opening of sphincter valves, lesions and/or scarring within the ducts, and/or pseudocysts (accumulations of fluid and tissue debris).
Complications from blockages within the bile ducts can very serious, and include infection of the common bile duct 108 (cholangitis) and inflammation of the pancreas 114 (pancreatitis) and potentially lead to death. Accordingly, it is important to address such a blockage so as to restore adequate drainage through the affected duct. In some cases, the obstruction may not be amenable to a surgical cure or bypass, and, instead, requires a palliative drainage procedure. A palliative drainage procedure is designed to prolong the life of the patient and to make the patient more comfortable when the condition of the patient is incurable.
In cases where a patient may have a biliary obstruction, Endoscopic Retrograde Cholangiopancreatography (ERCP) has been used by clinicians as the standard procedure to perform palliative biliary drainage over the more invasive Percutaneous Transhepatic Biliary Drainage (“PTBD”) approach. The ERCP approach is an endoscopic procedure that combines upper gastrointestinal (GI) endoscopy and x-rays to treat problems of the bile and pancreatic ducts. For example, as shown in FIG. 3, during an ERCP procedure, an endoscope 122 is inserted into a patient's mouth, down the esophagus, into the stomach, passing into the lumen of the duodenum 120 to a position adjacent the ampulla of Vater 118. The endoscope 122 provides the initial access and direct visualization of the general area of treatment.
The endoscope 122 generally includes a proximal end (not shown), a distal end 124, and at least one lumen extending the length thereof. The distal end 124 of endoscope 120 generally includes a side opening in fluid communication with the lumen, such that additional medical devices may emerge from endoscope 122 from this side opening. It is these additional medical devices, which pass through endoscope 122, which are used to navigate and treat the abnormal pathologies within the desired duct. In particular, a biliary catheter 126 is advanced through endoscope 122 until the distal tip of biliary catheter 126 emerges from the endoscope 122 side opening and is advanced to the ampulla of Vater 118 leading to the common bile duct 108 and the pancreatic duct 112.
A guidewire (not shown) may be used in conjunction with biliary catheter 126 to aid in accessing a desired location within the biliary tree 128. For example, the guidewire is inserted in an opening at a proximal end of biliary catheter 126 and guided through the catheter lumen until it emerges from the distal end of the biliary catheter 126. The biliary catheter 126 is then advanced over the guidewire until the distal end of the catheter is positioned in the biliary tree 128 at the desired location. The biliary catheter 126 is now in a position for delivery of contrast media within the desired duct, wherein the contrast media allows for fluoroscopic visualization of anatomical detail within the biliary tree 128. The fluoroscopic visualization may reveal abnormalities and/or blockages within the common bile duct 108 that may require treatment, such as biliary drainage.
While ERCP enjoys a high success rate, biliary cannulation fails in approximately 5 to 20% of cases. For example, cannulation of the ampulla of Vater can be a daunting task for the clinician. In order to gain access to the ducts, the clinician must gently press the tip of the biliary catheter, or guidewire, into and through the opening of the ampulla of Vater. However, despite the best efforts of the clinician, cannulation of the ampulla of Vater will not occur through traditional “push-pull” techniques due to endoscopist inexperience, a distorted anatomy of the ampulla of Vater due to tumor invasion of the duodenum or ampulla, surgically altered anatomy, and/or complex biliary structures. In these instances, a clinician may probe the ampulla for an extended period of time with little success. Prolonged probing may further cause inflammation of the ampulla, wherein each attempt at cannulation increases trauma to the surrounding tissue, and subsequently, increases the discomfort experienced by the patient.
Advancements in the field of gastrointestinal endoscopy have provided clinicians with the ability to perform Endoscopic Ultrasound Guided Biliary Drainage (EUS-BD) in cases where traditional ERCP has failed or may not be administered. In particular, Endoscopic Ultrasound-Guided Fine-Needle Aspiration (EUS-FNA) has been used to cannulate a biliary duct via an EUS/ERCP rendezvous technique. For example, as shown in FIG. 4, under a rendezvous technique, a clinician may advance an EUS endoscope 122 into the lumen of a patient's duodenum 120 to a position in which bile ducts may be visualized (e.g., via endosonography). The clinician may then advance an FNA needle 130 into the common bile duct 108 under EUS guidance by puncturing trans-duodenally, as indicated by arrow 132. After confirmation of bile duct puncture, a guidewire 134 may then be advanced distally through the bile duct 108 and across the ampulla of Vater 118. When the guide wire has passed through the ampulla into the duodenum 120, an endoscope exchange is performed, wherein the EUS scope 122 is withdrawn, leaving the guidewire 134 in place, and a side-viewing endoscope (e.g., duodenoscope) is then passed into the duodenum 120 adjacent the EUS-placed guidewire 134. The guidewire 134 is then grasped with a snare or forceps for subsequent over-the-wire cannulation (e.g., via biliary catheter), upon which access to the common bile duct 108 is achieved and a standard ERCP procedure can then be performed (e.g., open blocked ducts, break up or remove gallstones, remove tumors in the ducts, insert stents, and/or endoscopic sphincterotomy). It should be noted that, in other EUS/ERCP rendezvous procedures, access to the common bile duct 108 is not limited to trans-duodenal access, as illustrated in FIG. 4. For example, access to the common bile duct 108 may be achieved trans-gastrically, such that the FNA needle 130 is advanced through the gastric wall of the stomach and into the common bile duct 108 under EUS guidance.
The EUS/ERCP rendezvous technique may be a preferred approach for many endoscopists because of the less invasive nature it provides, particularly for biliary drainage. However, this approach may have many drawbacks. For example, the rendezvous technique generally requires significant skill on behalf of the clinician due to a lack of currently available tools designed specifically for successful guidewire tracking. Specifically, current needle designs are rigid, thereby severely limiting the clinician's ability to direct the guidewire. Furthermore, biliary drainage via the rendezvous technique may not be possible if the guidewire is unable to be advanced through the ampulla because of difficult angulation or a tight distal biliary stricture. Accordingly, biliary drainage by needle rendezvous technique may require repeat punctures with different angles often resulting in a prolonged, labor-intensive procedure with the risk of shearing the guidewire and/or biliary leakage. Further difficulties currently observed by clinicians performing the EUS/ERCP rendezvous technique are difficulties advancing or directing the guidewire across an obstruction, difficulty achieving penetration into the biliary duct, clinical complications, such as pancreatitis, due to ductal trauma. Furthermore, the required scope exchange between EUS endoscope and an ERCP scope for guidewire retrieval can be cumbersome and plagued with difficulties.